call exit_hook with error message (fixes #630)

CHANGELOG

@@ -5,6 +5,7 @@ This file contains a log of major changes in dehydrated
 ## Changed
 - OCSP refresh interval is now configurable
 - Implemented POST-as-GET
+- Call exit_hook on errors (with error-message as first parameter)
 
 ## Added
 - Initial support for tls-alpn-01 validation

dehydrated

@@ -432,6 +432,7 @@ _sed() {
 # Print error message and exit with error
 _exiterr() {
   echo "ERROR: ${1}" >&2
+  [[ -n "${HOOK:-}" ]] && "${HOOK}" "exit_hook" "${1}" || true
   exit 1
 }
 

docs/examples/hook.sh

@@ -178,10 +178,14 @@ startup_hook() {
 }
 
 exit_hook() {
+  local ERROR="${1:-}"
+
   # This hook is called at the end of the cron command and can be used to
   # do some final (cleanup or other) tasks.
-
-  :
+  #
+  # Parameters:
+  # - ERROR
+  #   Contains error message if dehydrated exits with error
 }
 
 HANDLER="$1"; shift